1. Field of the Invention
The present invention relates to a vehicle seat having a frame member, a cushion material and a support member (a member supporting the cushion material above the frame member).
2. Description of the Related Art
JP-A-2010-253242 discloses this kind of vehicle seat. This vehicle seat has a frame member that configures a seat frame, a cushion material that configures an outer shape of the seat and can elastically support a passenger, and a support member. The support member has a frame-shaped member that can be engaged to front and rear of the frame member, and a planar member that is attached to the frame-shaped member in a tensioned state. The frame-shaped member is a rectangular frame member and has a pair of rod-shaped parts (parts configuring sides of the frame-shaped member) extending in a front-rear direction of the seat. The planar member is a planer (sheet-like) material configured by weaving a thread material of natural or synthetic fabric.
In a related-art, the planar member is arranged on the frame-shaped member, and then, ends of the planar member are wound on the respective rod-shaped parts, are inwardly bent and sewed to a backside of the planar member. Accordingly, the planar member is attached to the frame-shaped member in a tensioned state, and then, the cushion material is supported by the planar member with the frame-shaped member being engaged to the frame member.
Incidentally, according to the above support member, when the tension of the planar member is insufficient, the planar member deviates from the frame-shaped member (the planar member is relatively rotated around the rod-shaped parts), so that sufficient support performance of the cushion material may not be obtained. Therefore, it is necessary to attach the planar member to the frame-shaped member while sufficiently applying tension to the planar member, which would cause the operation of attaching the planar member to be troublesome.
In view of this problem, JP-A-2011-254952 discloses a technique of arranging a planar member in a tensioned state beforehand in a cavity of a molding die when molding a frame-shaped member (made of resin). Then, by injecting a raw material (melted resin) for molding into the molding die, it is possible to integrally attach the planar member while molding the frame-shaped member.
However, according to the technique disclosed in JP-A-2011-254952, the planar member (thread material) may be partially broken due to heat at the molding. Therefore, the tension of the planar member is partially weakened, so that the support performance of the cushion material may be deteriorated.
Therefore, both the above techniques cannot always be adopted, considering the performance (the support performance, the operability and the like) of the support member.